Carbon monoxide compounds

The mechanism of poisoning automobile exhaust catalysts has been identified (71). Upon combustion in the cylinder tetraethyllead (TEL) produces lead oxide which would accumulate in the combustion chamber except that ethylene dibromide [106-93-4] or other similar haUde compounds were added to the gasoline along with TEL to form volatile lead haUde compounds. Thus lead deposits in the cylinder and on the spark plugs are minimized. Volatile lead hahdes (bromides or chlorides) would then exit the combustion chamber, and such volatile compounds would diffuse to catalyst surfaces by the same mechanisms as do carbon monoxide compounds. When adsorbed on the precious metal catalyst site, lead haUde renders the catalytic site inactive. 

Hb-CO - hemoglobin-carbon monoxide compound, the compound formed by CO and blood hemoglobin, whereby the oxygen (Hb-02, oxyhemoglobin) becomes displaced. 

The use of cyclopentadienyl-carbon monoxide compounds of Mn, as anti-knock agents in fuels, has been known for some time. In recent years the use of methylcyclopentadienyl manganese tricarbonyl (MMT) as an antiknock agent for gasoline has become more widespread, due to the decline in use of Pb alkyl compounds. 

Methanol carbon disulfide thallium disulfuram nitrobenzene Nitrobenzene carbon monoxide compounds of As quinine Certain organic solvents, i.e., hexane, acrylamide methyl-n-butyl ketone... 

Fig. 13. Carbon monoxide compound of the oxygen-transporting respiratory enzyme. (From Warburg.)...

The inferences dealt with in the last paragraph are of the crudest. In regard to two of the heme proteins, mammalian hemoglobin and myoglobin, but more particularly the former, much more information is available. We shall deal first with hemoglobin. This has been studied mostly in the form of the carbon monoxide compound of horse hemoglobin, which is one of the best characterized of all proteins, and indeed was the first to be studied in the ultracentrifuge either by the equilibrium... 

There are, however, also other reasons in support of the assumption that heme-linked groups in ferrocytochrome are affected by changes in pH. Below pH 4 and above pH 13 ferrocytochrome c is autoxidizable. Between pH 3 and pH 12 no carbon monoxide compounds are formed but at pH 2... 

Reduction of the peroxidase with hydrosulfite gives a red solution of ferroperoxidase with the bands 694.5 (narrow) and 558 mp (broad and flat). On shaking with air the ferroperoxidase is reoxidized, apparently without the formation of an oxyferrous compound. It thus differs in this respect from hemoglobin. The ferroperoxidase gives a red carbon monoxide compound with two bands at 678 and 545.5 mp. The intensity and size resemble the bands of carbon monoxide hemoglobin, but are displaced 8 mp toward the red. 

Potato phenolase and its carbon monoxide compound, according to Kubowitz (1938), presented only the typical protein absorption at 275 m/x, and there were no other specific absorption bands in the near ultraviolet nor in the visible range of the spectrum. No quantitative data were given, but the enzyme at a concentration of 10 mg./ml. was... 

Warburg (1949), developing the analogy of the behavior of phenol oxidase and hemocyanin against carbon monoxide and the difference of their absorption spectra, predicted that laccase, which is blue and is uninhibited by carbon monoxide, must be a nondissociating compound of oxygen with the monovalent copper present. But the reaction of hemocyanin with carbon monoxide was re-examined carefully by Rawlinson (1940) who found, contrarily to Root (1934), that hemocyanin does not form a carbon monoxide compound at all. 

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